Domingos Candiota Chula

Accuracy of Physical Examination and Intra‐Access Pressure in the Detection of Stenosis in Hemodialysis Arteriovenous Fistula

Both physical examination (PE) and intra‐access pressure (IAP) measurements have been used in the identification of stenosis in an arteriovenous access. The aim of this study was to evaluate the accuracy of PE and IAP in the diagnosis of arteriovenous fistula (AVF) stenosis. A total of 84 patients were enrolled in the study (54% men, mean age of 50.7 ± 12.7 years and mean AVF patency of 24.9 ± 7.8 months, 52% radiocephalic). Abnormalities of pulse and thrill were used as the diagnostic tools for the detection of stenosis using the physical examination. For IAP, stenosis was suspected when the ratio between IAP at the arterial puncture site and the mean blood pressure was <0.13 or >0.43. The diagnosis of stenosis was confirmed by Doppler ultrasound (DU). Sensitivity (S), specificity (SP), positive predictive value (PPV), negative predictive value (PNV), and accuracy were calculated for the two early detection tests. According to DU, 50 (59%) AVF were considered positive for the presence of stenosis. Fifty‐six (66%) AVF were considered positive for the presence of stenosis by PE and 34 (40%) by IAP. S, SP, PPV, and NPV for PE and IAP were 96%, 76%, 86%, and 93% and 60%, 88%, 88%, and 60%, respectively. The accuracy for PE and IAP was 88% and 71%, respectively. PE proved to be an accurate method for the diagnosis of stenosis and should be part of all surveillance protocols of stenosis detection in AVF.

Minocycline-EDTA Lock Solution Prevents Catheter-Related Bacteremia in Hemodialysis

There is growing concern about the development of antibacterial resistance with the use of antibiotics in catheter lock solutions. The use of an antibiotic that is not usually used to treat other serious infections may be an alternative that may reduce the clinical impact should resistance develop. We conducted a randomized controlled trial to compare a solution of minocycline and EDTA with the conventional unfractionated heparin for the prevention of catheter-related bacteremia in hemodialysis patients during a period of 90 d. The study included 204 incident catheters (27.8% tunneled); 14 catheters were excluded because of early dysfunction and 3 because of protocol violations. We observed catheter-related bacteremia in 19 patients in the heparin group (4.3 per 1000 catheter-days) and in 5 patients in the minocycline-EDTA group (1.1 per 1000 catheter-days; P = 0.005). We did not detect a significant difference in the rate of catheter removal for dysfunction. Catheter-related bacteremia-free survival was significantly higher in the minocycline-EDTA group than in the heparin group (P = 0.005). In conclusion, a minocycline-EDTA catheter lock solution is effective in the prevention of catheter-related bacteremia in hemodialysis patients.

Stenosis in hemodialysis arteriovenous fistula: evaluation and treatment.

Vascular access complications are one of the main causes associated with an increase in morbidity and mortality in stage 5 chronic kidney disease patients. The arteriovenous fistula is regarded as the vascular access of choice for hemodialysis (HD) because of its superior patency and lower complication rates. Stenosis is considered the major cause of dysfunction of arteriovenous fistula. Despite the relatively low thrombosis rates of arteriovenous fistula, surveillance programs are necessary for detection of stenosis. We report a case of a HD patient who had never achieved an adequate Kt/V since the start of maintenance HD. During the investigation, abnormal findings were found on physical examination of the fistula, in addition to an alteration in intra‐access pressure (IAP) measurements. A venous stenosis was diagnosed by Doppler ultrasound and then promptly treated with percutaneous transluminal angioplasty. The purpose of the discussion is to highlight the peculiarities of arteriovenous fistulae, methods of surveillance, including physical examination, IAP, recirculation, and measurements of blood flow, and the importance of the correction procedures for the stenosis.

Interventional Nephrology in Brazil: Current and Future Status

The care of chronic kidney disease patients frequently involves many diagnostic and interventional procedures. Most of these procedures are currently performed by radiologists, vascular surgeons, and general surgeons. This has caused fragmented medical care, which has led many nephrologists to introduce a new paradigm, often referred as interventional nephrology (IN). The aim of this study was to establish the extent of involvement of the Brazilian nephrology community with regard to specific IN procedures. From October 2004 to February 2005, questionnaires were sent by e‐mail to all 2500 nephrologists throughout Brazil. The enrollment questionnaire was composed of five sections, with questions about renal biopsy, specific training in ultrasonography, peritoneal dialysis access (insertion of peritoneal catheters guided or not by peritoneoscopy), hemodialysis vascular access (ability to place tunneled catheters, construction of arteriovenous fistulas, and other vascular access procedures), and the nephrologists interest in being trained in IN. A total of 239 nephrologists answered the questionnaire. Only 18% of Brazilian nephrologists perform kidney biopsy guided by ultrasonography assisted by a radiologist. On the other hand, 42% of them reported that this procedure was done without any image support. Most of the respondents (85%) indicated that they were not formally trained to perform renal ultrasonography. When asked about peritoneal dialysis catheter placement, 66% of the respondents reported that they referred their patients to a surgeon for this procedure. The insertion of peritoneal dialysis catheters guided by peritoneoscopy was reported by 3% of the respondents. Similar to the results for peritoneal dialysis catheter placement, the majority of the respondents (77%) indicated no training in the insertion of tunneled catheters for temporary hemodialysis. Regarding the interest of nephrologists to participate in an IN program, the great majority (87%) responded that they would like to be trained in these procedures. Most nephrologists are not trained in IN procedures. Therefore, in Brazil, it will be necessary to develop training centers for IN that will allow nephrologists to optimize nephrology care.

Complications of the peritoneal access and their management.

Although peritoneal catheter insertion is relatively considered a minimal invasive procedure, it is associated with some complications. These complications are divided into mechanical (bleeding, visceral perforation, dialysate leaks, catheter dysfunction, hernia formation, cuff extrusion) and infectious (early peritonitis, surgical wound, tunnel and exit site infections). It is well recognized that the appearance of these complications can increase morbidity and the chance of peritoneal dialysis treatment failure. Independent of the insertion technique, the operator must be prepared to an immediate recognition and adequate management of complications. Pre-operative evaluation and identification of potential risk factors are essential to prevent them.

Acute kidney injury in patients infected by H1N1 - clinical histological correlation in a series of cases

INTRODUCTION Influenza A (H1N1) virus was first reported on April 2009 and, since then, several studies have reported the characteristics concerning the clinical presentation and pulmonary involvement. However, accurate information about the acute kidney injury (AKI) and kidney histopathological findings in these patients remain scarce. OBJECTIVE To describe the kidney histopathological findings of 6 patients with H1N1 who developed AKI and underwent kidney biopsy, correlating them with clinical features. METHODS We studied six patients admitted to Hospital de Clínicas UFPR with a PCR-confirmed diagnosis of H1N1who developed ARF and underwent kidney biopsy. We reviewed their medical file and the microscopy findings of the biopsy. RESULTS Clinical and/or laboratory evidence of AKI was present in all cases, and only one did not present oliguria. Kidney tissues revealed glomerular lesions in two patients: one patient, with systemic lupus erythematosus, showed changes consistent with lupus nephritis class III A-C according to the ISN/RPS 2003 and focal thrombotic microangiopathy; the other one had intercapillary nodular glomerulosclerosis, but without clinical or laboratory evidence of diabetes. Vacuolar degenerative tubular changes were present in all cases, with focus of oxalosis in two cases. Mild to moderate atherosclerosis was found in two patients. CONCLUSION In this study, varying degrees of vacuolar degenerative tubular changes were present in all patients, but there were no signs of acute tubular necrosis. It seems that in the present study a prerenal cause of acute renal failure was the main involved mechanim to explain the cause of renal failure in these patients.

Percutaneous and surgical insertion of peritoneal catheter in patients starting in chronic dialysis therapy: a comparative study.

Percutaneous peritoneal catheter insertion can be performed by trained nephrologists. The objective of this study was to compare the outcome of peritoneal dialysis (PD) catheters percutaneous inserted with the traditional surgical technique. One hundred twenty‐one PD catheters were placed in 121 stage‐5 Chronic kidney disease patients using three techniques: percutaneous insertion (Group P, n = 53), percutaneous insertion guided by radioscopy (Group R, n = 26), and surgical insertion (Group S, n = 42). The mean age of the whole cohort was 57 ± 16 years and 54% were male. Patients and catheter outcomes were followed up prospectively for 19 months. Gender, age, body mass index, previous abdominal surgeries, and the prevalence of diabetes mellitus were not significantly different among the groups as well as the incidence of bleeding and the presence of catheter dysfunction. In addition, the incidence of exit‐site infections and peritonitis was not significantly different among the groups. Finally, the survival catheter rate was not significantly different by the end of the follow‐up of 19 months (70% in P group, 85% in R, and 70% in S group (log rank = 0.88, p = 0.95). The outcome of percutaneous implanted catheters, which were inserted by a trained nephrologist, did not demonstrate to be inferior as compared with the traditional surgical approach.

Acute renal failure and haemorrhagic syndrome secondary to toxin of caterpillars (Lonomia obliqua)

Accidental poisoning with caterpillars has become increasingly frequent in southern Brazil, partly due to deforestation and elimination of natural predators [1]. Caterpillars are the larval stage of moths and butterflies and are found worldwide [2]. Accidental contact with caterpillars bristles induces allergic and toxic signs and symptoms that range from mild cutaneous reaction to severe systemic reactions, depending mainly on the number and species of the caterpillar involved. Symptoms include local irritation, urticarial dermatitis, allergy, ocular injuries, osteochondritis, haemorrhage secondary coagulopathy and acute renal failure. Haemorrhagic complications including intra-cerebral can result in mortality [2,3].

Peritoneal Dialysis Access: What’s the Best Approach?

There are many procedures for placement of an intraabdominal peritoneal catheter for peritoneal dialysis. Each one has its own advantages and disadvantages. Although the blind technique with a trocar was the initial procedure utilized, over the years interventional nephrologists and surgeons have evolved to more modern techniques that allow more direct visualization of the peritoneal cavity, minimizing complications catheter-related. Novel techniques such as peritoneoscopy and laparoscopy appear to be associated with a reduced number of exit site infections, lower incidence of peritonitis, decreased risk of leakage and improved catheter survival. Since some studies have not seen all these benefits associated with these procedures, one recognizes the importance of the experience obtained with each procedure in every center and the impossibility of generalization.

A case of renal recovery in atypical hemolytic uremic syndrome treated with eculizumab

Atypical Hemolytic Uremic Syndrome (aHUS) is a rare, life-threatening disease that can occur at any age and be sporadic or familial. aHUS is caused by an uncontrolled activation of the complement system. Plasma Exchange (PE) has been the standard treatment for years with poor results, leading approximately 40% of patients to end-stage renal disease (ESRD) or death during the first clinical manifestation. Eculizumab, an humanized monoclonal antibody directed against complement component C5, has emerged in the last few years as a new therapheutic aproach with promising results. Our goal is to present a case of an adult patient where eculizumab was sucessfully used as upfront therapy avoiding the potential significant morbidity of PE.